> does it mean if we want to add a new SoC plat/mach, we will send> patches againest this tree?

Yes. Or against latest mainline tree from Linus.

> will this tree merge into rmk's tree? then rmk's tree will only manage> arm common codes?

Something like that. The exact details will be fleshed out as we go. The idea is to give a round of review from a higher point of view to make sure no opportunities for code reuse is missed, etc. The mechanics of how this code transitions from this tree into mainline during the merge window is secondary.